Q1
Not really. The game's flow was good. All the battles were fun and doable, and there weren't any frustrating puzzles that could take ages to solve. All the solutions to get the story going were always within the area.
Q2
Sheila definitely would be the best character for me. She was really well-developed and likeable. I'd definitely be interested to experience more of her adventures. The other characters I liked (and would like to see more of): The
Bouncer Book Person

, The Cop, The Priest, The Lady in the red dress, The Don.
Q3
I did lose a few times. I lost the first time to the doorman, but I managed to beat him on the second try. I also lost to the Gang leader/Godfather, this time quite a number of times, because I exhausted all the options before trying out the 'potion'. Admittedly I first played this part in the contest version of the game which starts at the bar, and so the 'Potion' in my inventory was a bit confusing as I thought it was a healing item rather than alcohol to be used in conversations. Haha. I also lost once to the Priest because I thought pretending to obey him would throw him off, but instead I got an instant game over. I managed to beat him on the second try though. So there weren't any parts where I was stuck for long.
Q4
I assume that refers to the Godfather battle? If so, see above on my experience with it. I remember though the Red-dress woman had that option too as well as the Rock Mage. I think I tried drinking the wine in both instances, though I chose the 'sip' option rather than 'gulp'. I did like very much that it was possible to win the Red-Dress girl via two different ways. One time I did it via intimidation, the other time I did it via cheering her up when she fell in depression. So that was a very nice touch. I would not change any of that.
Q4 (again, haha, you mean Q5)
I suppose more dialogue options would be great. It might be harder to event with more options, but it would be nice. Maybe not all of them will be available right away, kind of like how here we learnt the joke skill only after beating the doorman, so maybe the same mechanic can be applied in future installments.
Also as something I suggested during my review earlier, perhaps your attire can play a role in how effective each dialogue option is for you. Maybe a seductive outfit for example makes flirting easier, or a scary outfit makes intimidate succeed more of the time, etc.